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marcus.erl |
/*
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* Copyright (c) 2000-2001 Christoph Hellwig.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL").
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Veritas filesystem driver - shared subroutines.
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*/
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include "vxfs_extern.h"
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static int vxfs_readpage(struct file *, struct page *);
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static sector_t vxfs_bmap(struct address_space *, sector_t);
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const struct address_space_operations vxfs_aops = {
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.readpage = vxfs_readpage,
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.bmap = vxfs_bmap,
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.sync_page = block_sync_page,
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};
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inline void
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vxfs_put_page(struct page *pp)
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{
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kunmap(pp);
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page_cache_release(pp);
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}
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/**
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* vxfs_get_page - read a page into memory.
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* @ip: inode to read from
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* @n: page number
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*
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* Description:
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* vxfs_get_page reads the @n th page of @ip into the pagecache.
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*
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* Returns:
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* The wanted page on success, else a NULL pointer.
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*/
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struct page *
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vxfs_get_page(struct address_space *mapping, u_long n)
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{
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struct page * pp;
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pp = read_mapping_page(mapping, n, NULL);
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if (!IS_ERR(pp)) {
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kmap(pp);
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/** if (!PageChecked(pp)) **/
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/** vxfs_check_page(pp); **/
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if (PageError(pp))
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goto fail;
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}
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return (pp);
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fail:
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vxfs_put_page(pp);
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return ERR_PTR(-EIO);
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}
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/**
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* vxfs_bread - read buffer for a give inode,block tuple
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* @ip: inode
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* @block: logical block
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*
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* Description:
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* The vxfs_bread function reads block no @block of
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* @ip into the buffercache.
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*
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* Returns:
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* The resulting &struct buffer_head.
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*/
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struct buffer_head *
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vxfs_bread(struct inode *ip, int block)
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{
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struct buffer_head *bp;
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daddr_t pblock;
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pblock = vxfs_bmap1(ip, block);
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bp = sb_bread(ip->i_sb, pblock);
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return (bp);
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}
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/**
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* vxfs_get_block - locate buffer for given inode,block tuple
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* @ip: inode
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* @iblock: logical block
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* @bp: buffer skeleton
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* @create: %TRUE if blocks may be newly allocated.
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*
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* Description:
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* The vxfs_get_block function fills @bp with the right physical
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* block and device number to perform a lowlevel read/write on
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* it.
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*
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* Returns:
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* Zero on success, else a negativ error code (-EIO).
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*/
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static int
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vxfs_getblk(struct inode *ip, sector_t iblock,
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struct buffer_head *bp, int create)
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{
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daddr_t pblock;
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pblock = vxfs_bmap1(ip, iblock);
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if (pblock != 0) {
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map_bh(bp, ip->i_sb, pblock);
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return 0;
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}
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return -EIO;
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}
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/**
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* vxfs_readpage - read one page synchronously into the pagecache
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* @file: file context (unused)
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* @page: page frame to fill in.
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*
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* Description:
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* The vxfs_readpage routine reads @page synchronously into the
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* pagecache.
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*
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* Returns:
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* Zero on success, else a negative error code.
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*
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* Locking status:
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* @page is locked and will be unlocked.
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*/
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static int
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vxfs_readpage(struct file *file, struct page *page)
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{
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return block_read_full_page(page, vxfs_getblk);
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}
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/**
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* vxfs_bmap - perform logical to physical block mapping
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* @mapping: logical to physical mapping to use
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* @block: logical block (relative to @mapping).
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*
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* Description:
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* Vxfs_bmap find out the corresponding phsical block to the
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* @mapping, @block pair.
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*
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* Returns:
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* Physical block number on success, else Zero.
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*
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* Locking status:
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* We are under the bkl.
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*/
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static sector_t
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vxfs_bmap(struct address_space *mapping, sector_t block)
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{
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return generic_block_bmap(mapping, block, vxfs_getblk);
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}
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